Molding sand



' Patented Sept..23, 1930 UNITED STATES PATENT oFmcE III-EON LOUIS MATHIEU, OI RO'UEN, FRANCE, ASSIGNOR TO SOGIETE ANONYME IDES -HAUTS-FOURNEAUX ET FONDERIES DE MEUBTEE-ET-MOSELLE, FRANCE PONT-A-MOUSSON, OF PONT-A-MOUSSON,

MOLDING SAND Ho Drawing. Applicationflled December 29, 1928, Serial No. 329,204, and in France April 27, 1928.

This invention relates to a composite sand or molding material especially adapted for use in casting pipes'by the centrifugal meth d and comprising sand together with a certain amount of coal tar, the amount of coal tar being preferably about 1 or 2 per cent by volume.

The proportions in the composition may be, for instance, as follows:

1o Parts by volume Siliceous sand 40 Old sand Olayey sand 13 15 Goal tar 1 The improved molding material offers great advantages, chiefly when the pipes are cast by the centrifugal process in a sand mold contained in a metal mold made in one piece. In such a case, not only the amount of'sand required should be reduced to a minimum but also the sand should allow the metal to be cast without'an preliminary drying of the a sand. The san must also be used without any coating adapted to prevent its adhesion to the cast metal, and the pipe should be readily removable from ,the mold after the v casting. This latter operation is made more so difiicult due to the fact that the pipe usually has a raised edge or annular bead which tends to prevent the removal of the cast pipe from 'the mold.

' Thecomposite sand or molding material 85 according to the invention answers the above requirements. It possesses a eat cohesion and provides for casting oper tions without preliminary drying and without any'preliminary coating of an expensive nature.

40 Duringthe casting operation, there is prowill depend upon the dimensions of the pipes or like pieces to be cast.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

A molding material comprising the follow ing substances:

Parts by volume siliceous sand About 40 Old sand "5;-" About 20 Olayey sand About 13 Goal tar -About 1 In testimony whereof -I have signed my name to this specification.

LEON LOUIS MATHIEU.

duced a distillation of the tar, thus automatically covering the mold with a layer rotect- .ing it against the cast metal. After t ecasting, the tar is burnt away, whereby the sand is disaggregated, so that it will not materially oppose the discharge of the pipe-and the exit of its said raised edge.

Obviously, the above mentioned composi tion of the sand is example. The proportion of tar employed given solely by way of 

